diff --git a/Gemfile b/Gemfile
index 9f94721..ae03e48 100644
--- a/Gemfile
+++ b/Gemfile
@@ -8,7 +8,7 @@ gem 'rails', '~> 5.2.2'
 # Use postgresql as the database for Active Record
 gem 'pg', '>= 0.18', '< 2.0'
 # Use Puma as the app server
-gem 'puma', '~> 3.11'
+gem 'puma', '~> 4.3'
 # Use SCSS for stylesheets
 gem 'sass-rails', '~> 5.0'
 # Use Uglifier as compressor for JavaScript assets
diff --git a/Gemfile.lock b/Gemfile.lock
index be137d2..36ae872 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -264,7 +264,8 @@ GEM
     pry-rails (0.3.9)
       pry (>= 0.10.4)
     public_suffix (3.0.3)
-    puma (3.12.0)
+    puma (4.3.8)
+      nio4r (~> 2.0)
     pundit (2.1.0)
       activesupport (>= 3.0.0)
     rack (2.0.6)
@@ -464,7 +465,7 @@ DEPENDENCIES
   omniauth-vkontakte
   pg (>= 0.18, < 2.0)
   pry-rails
-  puma (~> 3.11)
+  puma (~> 4.3)
   pundit
   rails (~> 5.2.2)
   rails-controller-testing